In many instances proper medical treatment requires accurate doses of medicine to be administered at clearly defined intervals. In such cases it is important that the patient keep an accurate record of his ministrations to be sure that he is abiding by instructions and to permit the attending physician to evaluate the efficiency of the treatment with full confidence in the dosage and timeliness of the ministrations. This is not always easy: people who need medicinal treatment are ill and typically not well disposed to keeping accurate records. Often they are aged or children, which makes accurate record keeping even less likely. One area of concern is the treatment of asthmatics using metered dose inhalator canisters. The canister is installed in an applicator which receives the canister in inverted orientation. The bottom of the canister is facing upward. Actuation is effected by pressing down on the bottom of the canister, which causes the nozzle to be tripped by the structure of the applicator to release a metered dose of medicine. The structure of the applicator redirects the mist 90.degree. horizontally through a tube held between the patient's lips as the patient breathes in.
The metered dose inhaler canister is typically a metal container, and so it is not possible to tell accurately how much medicine or metered dosages are remaining. The patient is at risk to run out at an inopportune time, thus putting himself in jeopardy in many ways, including shortness of breath, choking, respiratory discomfort, and even hospitalization. The metered dose inhalers do not provide the user with daily dosing information. The patient, unless he or she records the information in a diary, has no real chance to remember what has been taken on any given day. The metered dose inhalers do not provide any historical information to the patient or the attending doctor. Unless the patient is very diligent in recording his daily dosing, there is no way he can keep an accurate record for any length of time. Patients tend to be very lackadaisical when recording or managing their medicine. Doctors cannot treat the asthmatic effectively if the information being communicated is poor quality or nonexistent. Because patients are concerned that they may run out of medicine, or do not know how much is remaining in the canister, they will tend to purchase an "extra" unit, an unnecessary expense. Patients are concerned that the medicine contained within the canisters can be harmful if not administered in a controlled manner. Steroids are commonly used in asthma medicines. Parents of young asthmatics in particular are concerned about the intake level of steroidal compounds.
The need for dosage monitoring is not limited to aerosol, atomized, gas or liquid form; it is needed as well for dispensing of solids such as powders and tablets and for candies, cough medicines, breath mints, stomach acid neutralizers and the like.